It's also possible that the child process is causing the segfault because of misconfiguration (e.g. broken environment variables).
And depending on the OS, abort() calls (via Py_FatalError) sometimes appear to be segfaults, so it could be any number of issues. (Aside - I'd love to replace the abort() calls with specific exit codes for configuration errors - they really mess up the crash data we see on Windows.)
I'll try some tests locally to see if this is reproducible, but if anyone can extract the original stdout/stderr from the buildbot, that would be helpful.